<![CDATA[We've talked before about the importance of recovery drills in AWS and why they must be performed on a regular basis. Ensuring successful backup and recovery is essential for handling data loss scenarios in order to minimize risks, such as data corruption. When you recover an instance in EC2 from an AMI or a snapshot, you are left with a new instance running in your account. Obviously this is not enough to ensure that recovery has been successful, meaning the application is up and running again, functioning at full capacity. In this article, we will discuss the various levels of testing associated with running backup verification for database servers hosted on Amazon EC2.
Three LevelsIn order for a recovered database instance to maintain functionality, you should verify both the instance and the data. Essentially, there are three levels of tests needed to verify that your backup is complete:
1. Host LevelMake sure the instance is running properly, the host has booted properly, and you are able to connect to it without interruptions. The first thing you want to do when you run an instance is to see that the first two EC2 CloudWatch status checks – the system status check and the instance status check – succeed on the instance.
- System Status Check – An underlying infrastructure physical host check that includes factors such as network connectivity and system power, for example. According to AWS, in order to fix issues, you can stop/start, or simply start a new instance.
- Instance Status Check – On the software and network configuration level, this check includes corrupted file system issues and malfunctioning startup configurations.
2. File System (check disk)Following these two host-level tests, you can run another type of check – a file system check. When you perform automated EBS volume backups, such as with Cloud Protection Manager, you want to make sure that the backup data is not corrupted. To do so, there are basic OS tools that test and ensure proper functionality:
- In Linux – You can perform a command called fsck (file system consistency check) on the file system.
- In Windows – The chkdsk command has tags that alter the basic integrity of the file system. Nevertheless, this test still performs the standard file system checks on the file level. After running chkdsk and ensuring that everything is running smoothly, you can confidently state that the file system has its integrity and there are no corrupted files.